Default unity timeline window looks like this (displays seconds) :
To sync animation and music I want it to display bars according to current BPM like in ableton:
You can change the timelines FPS display in the inspector of the timeline asset. Just change the beats per minute to beats per second. Make sure the timeline editor is set to display ‘frames’ under the gear menu. The catch is there may be a bit of error accumulation when the bps can’t be accurately expressed - e.g. 140bpm = 2.3333333… bps.